Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/compile_time_constants.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.compile_time_constant_evaluator;
 
 import 'common/resolution.dart' show Resolution;
 import 'common/tasks.dart' show CompilerTask, Measurer;
 import 'common.dart';
 import 'compiler.dart' show Compiler;
@@ skipping 335 matching lines @@
 
   ConstantExpression compileNode(Node node, TreeElements elements,
       {bool enforceConst: true}) {
     return compileNodeWithDefinitions(node, elements, isConst: enforceConst);
   }
 
   ConstantExpression compileMetadata(
       MetadataAnnotation metadata, Node node, TreeElements elements) {
     return compileNodeWithDefinitions(node, elements);
   }
-
-  void forgetElement(Element element) {
-    initialVariableValues.remove(element);
-    if (element is ScopeContainerElement) {
-      element.forEachLocalMember(initialVariableValues.remove);
-    }
-    if (element is FunctionElement && element.hasFunctionSignature) {
-      element.functionSignature.forEachParameter(this.forgetElement);
-    }
-  }
 }
 
 /// [ConstantCompiler] that uses the Dart semantics for the compile-time
 /// constant evaluation.
 class DartConstantCompiler extends ConstantCompilerBase {
   DartConstantCompiler(Compiler compiler)
       : super(compiler, const DartConstantSystem());
 
   ConstantExpression getConstantForNode(Node node, TreeElements definitions) {
     return definitions.getConstant(node);
@@ skipping 1072 matching lines @@
 class _CompilerEnvironment implements Environment {
   final Compiler compiler;
 
   _CompilerEnvironment(this.compiler);
 
   @override
   String readFromEnvironment(String name) {
     return compiler.fromEnvironment(name);
   }
 }